<?php if (!isset($username)):?>
<li id="loginli">
<?php echo anchor(site_url('login'), '登录');?>
</li>
<?php else:?>
<li id="meli">
<?php echo anchor(site_url('me'), $username);?>
</li>
<li>
<?php echo anchor(site_url('login/logout'), '登出');?>
</li>
<?php endif;?>